To investigate the influence of an Al-Zn-Mg-Cu alloy with as-homogenized and as-rolled initial microstructures on the tensile flow behavior, isothermal tensile tests were conducted on a GLEEBLE-3500 isothermal simulator at temperatures range 380-440 °C and strain rates range 0.05-1 s-1. The Johnson-Cook model, Hensel-Spittel model, and strain-compensated Arrhenius model were established, combined with a critical facture strain model. The evaluation of the models using the correlation coefficient (R) and the average absolute relative error (AARE) indicates that the strain-compensated Arrhenius model represents the flow behavior of the alloy more accurately. Shear bands were more pronounced in as-homogenized specimens, whereas dynamic recrystallization (DRX) was predominantly observed in as-rolled specimens. Fracture morphology analysis reveals that mixed fracture mechanism is prevalent in the as-homogenized specimen, while ductile fracture mechanism is predominant in the as-rolled specimen. The processing maps indicated that the instable region was reduced in the as-rolled specimen compared with the as-homogenized, and the optimal hot working windows for them were determined to be 410-440 °C & 0.14-1s-1 and 380-400 °C & 0.05-0.17 s-1, respectively.